Water Flow Detector WFD01

ABSTRACT

A water flow detector comprised of a check valve and parallel flow detection loop in which flow can be measured by monitoring the pressure differential as the difference between the water supply line pressure at the tee on the inlet side of the check valve (high pressure side) and the low pressure being at the tee connection on the downstream or outlet side of the check valve. The proportional water flow in the loop acts on a float which position is detected by optical and electronic means and enables the recognition of very small flows (small leaks) triggering an alarm to signal the leak.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Applicants' prior provisionalapplication, No. 62/708,650, filed on Dec. 18, 2017, and theaforementioned application is hereby incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

In residential and commercial building settings, water leaks often goundetected for significant periods of time, often with a high water andutility charge being the first indication the homeowner, building ownerand/or lessee receives of the leak.

The existence of a flow detection device to effectively monitor for, andnotify the homeowner, building owner and/or lessee of, inconspicuouswater leaks in the interior or on the exterior of a residence orcommercial building would serve the joint purposes of avoiding the highcost of wasted water and aid in water conservation. Until the subjectinvention, no economical or practical method existed (whether by someindicator light or audible alarm) to give an immediate indication whenwater is flowing through the water supply line to a structure todetermine if any flow at that time would indicate a probable leak.

SUMMARY OF THE INVENTION

This invention is a water flow detector which if properly installedbetween the residential or commercial structure and the existing watermeter will give immediate indication when water is flowing through thewater supply line to the structure when there should be no flow, so asto indicate a probable leak.

The WFDOI flow detector is a unique assembly of parts, material, andfunctional concepts or principles, which in their combined purpose inthis particular assembly, provides immediate alarm by a blinking light(and provision for connecting further remote alarm device) to indicatethere is flow in a water line (typically water supply line to a familyresidence or commercial structure) by monitoring the pressuredifferential across a combination of a flow detection piping loopconnected in parallel with a spring-return type check valve to beinstalled in the water line.

DESCRIPTION OF THE DRAWINGS.

Various embodiments of the invention are disclosed in the followingdetailed description and accompanying drawings.

FIG. 1 illustrates a typical installation of the WFDOI along with otherinstallation piping and typical check valve (spring-return type).

FIG. 2 illustrates the WFDOI assembly front view.

FIG. 3 illustrates the WFDOI assembly top view from FIG. 2 Section“A-A”.

FIG. 4 illustrates the WFDOI assembly left side view.

FIG. 5 illustrates the WFDOI assembly top view from FIG. 4 Section“B-B”.

FIG. 6 illustrates the WFDOI float chamber assembly front view.

FIG. 7 illustrates the WFDOI float chamber assembly left side view.

FIG. 8 illustrates the WFDOI assembly base front view.

FIG. 9 illustrates the WFDOI assembly base left side view from FIG. 8Section “C-C”.

FIG. 10 illustrates the WFDOI assembly base bottom view from FIG. 8Section “D-D”.

FIG. 11 illustrates the WFDOI assembly nylon rod float item 8 side viewand end view.

FIG. 12 illustrates the WFDOI assembly float chamber wall clear pipeitem 7 side view and end view.

FIG. 13 illustrates the WFDOI assembly float chamber bottom stop-spaceritem 6 side view and end view.

FIG. 14 illustrates the WFDOI assembly optical emitter mounting PVC item21 face view and end view.

FIG. 15 illustrates the WFDOI assembly optical receiver(phototransistor) mounting PVC item 22 face view and end view.

FIG. 16 illustrates the WFDOI assembly optical emitter mounting doublebacked tape item 19A face view and end view.

FIG. 17 illustrates the WFDOI assembly optical receiver(phototransistor) mounting double backed tape item 20A face view and endview.

FIG. 18 illustrates the WFDOI assembly side view and end view (typical).

FIG. 19 illustrates the WFDOI assembly circuit card schematic and otherconnections.

FIG. 20 is the list of material for the Circuit Card WX01.

FIG. 21 is the list of material for the WFDOI.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of exemplary embodiments toillustrate the principles of the invention. The embodiments are providedto illustrate aspects of the invention, but the invention is not limitedto any embodiment. The scope of the invention encompasses numerousalternatives, modifications and equivalent; it is limited only by theclaims.

Numerous specific details are set forth in the following description inorder to provide a thorough understanding of the invention. However, theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

FIG. 1 indicates a typical installation of the WFDOI (with its flowdetection water piping loop assembly and other internal parts notvisible since being enclosed in a 4-inch schedule 40 pvc pipe housing)along with other installation piping and typical check valve(spring-return type).

The check valve (to be selected by the installer) used for thisapplication is dedicated to this flow detection purpose, and should notbe confused with any other check valve which may be installed in thewater line. Most any typical spring-return type check valve (typically¾′ or larger) will be suitable and the spring rate is not critical (seefurther description below).

Briefly, some types of parts in the WFD01 flow detection and alarmsystem consist of:

-   pvc schedule 40 piping, white color-   pvc schedule 40 piping, clear-   pvc schedule 40 pipe fittings and using standard solvent joining    methods-   nylon float for position in water depending on pressure differential    and flow-   stainless steel washers and vinyl tubing for use as stops for float    travel-   optical electronics for detecting position of float-   electronic circuit card and batteries to work with optical    electronics and alarm light for indication that there is some water    flow downstream of the check valve-   alarm indicator light

For more detailed list of items in the assembly, refer to List ofMaterial for Water Flow Detector that is included as FIG. 20. The itemnumbers in that list (and item numbers on drawings) are referred to inthe following descriptions.

The flow detection assembly uses a flow detection piping loop connectedbetween tees on each side of the spring-return type check valve in thewater line in which flow is to be measured. Thus, the check valve andflow detection loop form a parallel piping combination, in which flowcan be measured by monitoring the pressure differential as thedifference between the water supply line pressure at the tee on theinlet side of the check valve (high pressure side, referred to as H forhigh at the tee and at the loop inlet) and the low pressure being at thetee connection on the downstream or outlet side of the check valve(referred to as L for low at the tee and at the loop outlet).

Referring to FIGS. 2, 3,4, and 5 (and to FIGS. 6 and 7 for more detailat float chamber), the flow detection loop flow path (using fromleft-right for horizontal reference and up-down for vertical reference)proceeds from the H connection tee through pipe connections (dependingon installation) to the measurement loop assembly inlet H (flowleft-to-right) pipe 1 (and coupling 1A and pipe IB), to elbow 2, tovertical (up) pipe 3, and to the vertical (up) float chamber inletcoupling 4, then through float bottom stop washer 5 and floatstop-spacer 6, vertically (up) through the clear pipe float chamber 7,to, through, and around the detector float 8, vertically (up) throughthe float chamber outlet (top) coupling 9 and float top stop washer 10,through pipe 12 to elbow 13, then horizontally (right) through elbow 15,then vertically (down) through vertical pipe 16, to elbow 17, thenhorizontally (right) through pipe 18B and coupling 18A to the loopassembly outlet (L connection) pipe 18, and then through other pipeconnections (depending on installation) to the tee at low L side of thecheck valve.

FIGS. 2, 3,4, 5, 6, and 7 shows the water flow path items in the pipingloop, including a float chamber section, and also shows some other partsoutside the water flow path, such as the optical-electronic items 19 and20 with their mounting devices 19A, 20A, 21, 22, and hose clamp 23 atthe float chamber, the electronic circuit card 24 which is connected bywiring to the optical items, the power supply battery pack 25, and thealarm light 26.

With the water line normally filled with water and with no flow, thepressure at both tees will be the same, thus differential pressure willbe zero.

When there is downstream water line flow (water usage or leak), itcauses a pressure decrease in the downstream piping and along thepipeline upstream of where the flow is going. That causes a proportionalpressure differential across the check valve and the parallel flowdetection piping loop, so, depending on the amount of flow anddifferential pressure, that flow can go through the flow detection loopand/or the check valve. For all amounts of flow, a small amount goesthrough the loop, including the float chamber for monitoring flow todetect that there is some amount of downstream flow (alarm point amountor more), but check valve flow depends on the downstream flow causinghigh enough differential pressure to open the check valve against itsspring.

The sensitivity of the flow detection loop is such that it can detect asmall amount of flow (small leaks) before the downstream flow is highenough to cause enough differential pressure to open the check valve.

A typical check valve may have a spring rate of 0.5 to 2 psi (or somevalves more or less). If the spring rate is 1 psi then for the valve toopen, there must be enough flow in the line downstream of the checkvalve to allow its outlet pressure to be at least 1 psi less than theinlet pressure of the valve. That is, the valve would start to open witha pressure differential of 1 psi across the valve. If the check valvewere alone in the line, without the parallel flow detection piping loop,then just a small amount of downstream flow would cause enoughdifferential pressure to start opening the valve.

However, the flow detection piping loop is connected in parallel withthe check valve and a small amount of flow will go through that loopwith any amount of pressure differential across the check valve greaterthan zero. So at very low downstream flow and differential pressureacross the parallel combination, all of the water line flow will gothrough the detection loop, until the flow has increased enough to causea pressure differential greater than the check valve spring pressure.When the check valve starts opening, it will carry most of theincreasing line flow, and a proportional small amount will continue toflow in the flow detection loop.

As the differential pressure causes flow through the float chamber andaround and through the float 8, it also causes force against the bottomof the float to add to its slightly-heavier-than-water buoyancy and thatdifferential force across the float lifts the float against gravityforce, to change its position in the float chamber 7. Since the floatchamber walls are clear which would otherwise allow the light beam fromthe emitter part of the optical electronics 19 to reach the receiverpart of the optical electronics 20 on the other side of the chamber,only the body of the float 8 blocks the light beam. When the flowincreases enough to increase the pressure differential causing enoughforce on the float to move it off the travel stop 6 in the bottom of thefloat chamber and up to a flow alarm set position (which also depends onthe position of the optical devices 19 and 20), that will allow thelight beam from emitter 19 to reach the receiver 20 to trigger theelectronic circuit card, 24, to turn on the blinking alarm light, 26, toindicate there is some amount of downstream flow, which could indicate apossible leak in the downstream water system.

Above the alarm flow, if the downstream flow continues increasingcausing a higher differential pressure, the float will be pushed up tothe stop, 10, in the top of the float chamber. The float will remainabove the alarm set flow position and the alarm light will continue toblink as long as the flow and differential pressure is more than thealarm set flow amount. When flow and differential pressure decreasebelow the alarm set amount, the float will drop to again block the lightbeam and turn off the blinking alarm light.

Greater Details Of Float Chamber. As flow occurs in the flow detectionloop, it is considered that most all of the pressure drop (pressuredifferential) between the tees will be across the float in the floatchamber, since it is expected that the flow resistance of the ¾ inchloop piping (in series with the float chamber) will not cause asignificant pressure drop compared to the float chamber. The flow in thefloat chamber in proportion to its pressure differential will depend onthe flow coefficient Cv of the float chamber, which will depend on theflow restriction in the flow paths area between the float and the wallsof the float chamber (about 90% of the flow area) and the hole throughthe float (about 10% of the flow area).

It has been observed that a flow rate of 6 ounces/minute (0.04687gallons/minute) raises the float by 0.4375 inches above the bottom stop.

The float weight equals 1.15 times weight of same volume of water. Thefloat is 1 inch long (1 inch height in the column of water), soadditional force of 0.15 inch of water is required to start lifting thefloat above the bottom stop. So to raise the float by 0.4375 inches willrequire pressure equal to (0.15+0.4375=0.5875) inches of water, and 1psi is same pressure as a column of water 27.7 inches high, so to raisethe float by 0.4375 inches will require pressure of 0.0212 psi, that is0.5875 * (1/27.7)=0.0212 psi.

As the float moves up from the bottom stop, most of the travel (up toabout 0.5 inches) the flow in gallons/minute (gpm) is proportional tothe square root of the differential pressure (psi=(inches ofwater+0.15)/27.7) and proportional to the flow coefficient Cv. That is,flow gpm=Cv * sq.rt.(psi). Then, using the above observed information tocalculate Cv, flow (0.04687 gpm)=Cv * sq.rt(0.0212 psi), andCv=0.04687/0.1456=0.322. So, at 0.5 inches float travel,psi=(0.5+0.15)/27.7=0.0234 psi, and using that equation, flowgpm=0.322 * sq.rt. (0.0234)=0.0493 gpm.

For defining of float position for leak detection alarm point, movementof the float to approximately 0.25 inch above the bottom stop((0.25+0.15)/27.7=0.0144 psi) should be enough to detect a water flow ofat least or more than 0.0387 gallons per minute (gpm). At that point thefloat will be high enough to allow enough light from the emitter 19 toreach the receiver 20 to cause the circuit card 24 to turn on theblinking light. But to allow for errors, if movement to 0.3125 inch isrequired, at that point the flow will be 0.0416 gpm.

As larger leaks or normal use causes downstream flow and pressuredifferential to continue increasing above the leak detection alarmamount, when the float nears the top stop (at about 0.625 inch floattravel), the float chamber Cv will decrease to about 0.0322 (10% of0.322) when the float hits the top stop. That is, the top stop causesflow around the float between float and walls of chamber to approachzero, but flow in float chamber continues through hole in float. Thereduced Cv means less flow through float chamber, but the differentialpressure force still holds the float against the top stop.

At that point the pressure differential will be about((0.625+0.15)/27.7)=0.0279 psi and float chamber flow=0.0322 * sq.rt.(0.0279)=0.0053 gpm.

As downstream flow and pressure differential continues increasing, thecheck valve will start opening at a differential pressure depending onthe check valve spring. If that is 1 psi, at that point float chamberflow=0.0322 * sq.rt.(I psi)=0.0322 gpm. For further downstream flowincrease, most of the flow will go through the check valve (but smallamount still going through float chamber) and further increase ofpressure differential will depend on the flow and check valve size andopening.

When downstream water flow stops, the float in the float chamber willdrop below the alarm point and the electronics will turn off theblinking light.

Circuit Card description (Ref. FIG. 6). The battery 25 supplieselectrical power to the circuit card 24, and the circuit card isconnected to receive input from the optical electronic devices, emitter19 and receiver 20 which inputs float position signal to the circuitcard, and output from the circuit card turns the blinking alarm light onand off.

The operation of the circuit card is centered around a low-power versionof the popular 555 timer integrated circuit of which various versionshave been used for many years, and the other types of parts on thecircuit card also have long histories.

The 555 timer, UI, is connected as an astable multivibrator, that is itsoutput is high (Vcc) part of the time and low (GND) another part of thetime. The high time (about 3 seconds) and low time (about 1 second) isset by the values of capacitor CI and resistors RA and RB.

When UI output is high, that turns off transistor QI, which then turnsoff emitter 19. When emitter 19 is off that causes phototransistor 20 tobe off, so the circuit at pin 2 of comparator U2.1 will be low, and pin6 of U2.2 will be low. Pin 3 of U2.1 and pin 5 of U2.2 will be atvoltage approximately 0.5 * Vcc. U2.1 switches its output (pin 1) basedon comparison of voltages at its inputs pin 2(−) and pin 3(+), so itsoutput will be high, that is its internal open-collector output will beoff and cannot conduct current into pin 7 to GND, so transistor Q2 willbe off which will turn off the blinking light 26. U2.2 switches itsoutput (pin 7) based on comparison of voltages at its inputs pin 6(−)and pin 5(+) so its output will be high, that is its internalopen-collector output will be off and cannot conduct current into pin 7to GND.

When UI output is low, that turns on transistor QI which turns onemitter 19, but if light fron 19 is prevented from reachingphototransitor 20, the outputs of U2.1 and U2.2 will still be off asmentioned above.

But if the float position is above the alarm position, when UI outputturns low, that will allow light from emitter 19 to reachphototransistor 20 which will turn it on to cause the voltage at inputpin 2 of U2.1 and input pin 6 of U2.2 to go higher than the inputs pin 3of U2.1 and pin 6 of U2.2 . The output pin 1 of U2.1 will switch low toturn on transistor Q2 to turn on the blinking light.

When the phototransistor turns off, either because the cycling UI outputgoes high, or float position goes below the alarm position, that causesthe output of U2.1 to turn off the blinking light.

A possible remote alarm could be turned on and off as follows: When thephototransistor turns on and causes the U2.2 pin 6 input to go higherthan pin 5 the output pin 7 of U2.2 will switch low, so, if an outputcircuit is connected, that will allow current to flow into U2.2 pin 7open-collector output to GND. When the phototransistor turns off theblinking light, the time delay by diode DI, resistors R12 and R13, andcapacitor C3 keeps U2.2 output low long enough for it to remain steadyduring about 2 cycles of the blinking light, and then to allow it to gohigh if phototransistor stays off after that time.

For more detailed list of material in the Circuit Card WX01, refer toList of Material for Circuit Card WX01 that is included as FIG. 21.

1. I claim a unique water flow detector piping loop device, WFD01,comprising a vertical-oriented inverted U-shape loop with means ofdetection, for detection of downstream flow in a water line; a) usingthe resulting differential pressure and proportional flow in the loopwhen it is connected in parallel with a spring-return type check valveinstalled in the water line; b) acting on a float in a clear-wall pipefloat chamber part of the loop by the flow differential pressure forceto position it upward against gravity; c) the loop piping and floatbeing sized so most of the loop differential pressure is across thefloat which position (at less than 0.5 inches water column, not affectedby water line static pressure) is detected by optical and electronicmeans to turn on blinking light; d) detecting (raising an alarm) forvery small flows before flow and differential pressure is high enough toopen check valve, continuing to alarm for larger flows as when checkvalve is open; and e) the vertical orientation of the piping loopallowing all parts of the WFD01 to be contained in a 4″ PVC pipevertically oriented cylindrical housing for protection and arranged sothe bottom part can be below ground for installation with the checkvalve and top part is above ground so the alarm light is visible.